0ct0pu5/moby
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

libnetwork: network.requestPoolHelper: don't defer in a loop

Browse source 
This function intentionally holds a lock / lease on address-pools to
prevent trying the same pool repeatedly.

Let's try to make this logic slightly more transparent, and prevent
defining defers in a loop. Releasing all the pools in a singe defer
also allows us to get the network-name once, which prevents locking
and unlocking the network for each iteration.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This commit is contained in:
Sebastiaan van Stijn 2023-07-22 17:36:54 +02:00
parent 32fcde6d9e
commit ad68883c5a
No known key found for this signature in database
GPG key ID: 76698F39D527CE8C
1 changed files with 18 additions and 12 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

30
libnetwork/network.go
View file

@ -1525,6 +1525,18 @@ func (n *Network) ipamAllocate() error {
}
func (n *Network) requestPoolHelper(ipam ipamapi.Ipam, addressSpace, requestedPool, requestedSubPool string, options map[string]string, v6 bool) (poolID string, pool *net.IPNet, meta map[string]string, err error) {
var tmpPoolLeases []string
defer func() {
// Prevent repeated lock/unlock in the loop.
nwName := n.Name()
// Release all pools we held on to.
for _, pID := range tmpPoolLeases {
if err := ipam.ReleasePool(pID); err != nil {
log.G(context.TODO()).Warnf("Failed to release overlapping pool %s while returning from pool request helper for network %s", pool, nwName)
}
}
}()
for {
poolID, pool, meta, err = ipam.RequestPool(addressSpace, requestedPool, requestedSubPool, options, v6)
if err != nil {
@ -1542,18 +1554,12 @@ func (n *Network) requestPoolHelper(ipam ipamapi.Ipam, addressSpace, requestedPo
return poolID, pool, meta, nil
}
// Pool obtained in this iteration is
// overlapping. Hold onto the pool and don't release
// it yet, because we don't want ipam to give us back
// the same pool over again. But make sure we still do
// a deferred release when we have either obtained a
// non-overlapping pool or ran out of pre-defined
// pools.
defer func() {
if err := ipam.ReleasePool(poolID); err != nil {
log.G(context.TODO()).Warnf("Failed to release overlapping pool %s while returning from pool request helper for network %s", pool, n.Name())
}
}()
// Pool obtained in this iteration is overlapping. Hold onto the pool
// and don't release it yet, because we don't want IPAM to give us back
// the same pool over again. But make sure we still do a deferred release
// when we have either obtained a non-overlapping pool or ran out of
// pre-defined pools.
tmpPoolLeases = append(tmpPoolLeases, poolID)
// If this is a preferred pool request and the network
// is local scope and there is an overlap, we fail the